Distributed data processing systems are widely used e.g. in networked computer applications. In such systems a plurality of workstations can access one or more servers to utilise data and or applications stored thereon. The network interconnecting the various system elements may comprise a dedicated network, or, more advantageously, a non-dedicated telecommunications network having appropriate bandwidth for carrying data traffic. A recent development in telecommunications technology has been the introduction of the asynchronous transfer mode (ATM) transmission protocol. In an ATM system, digitised traffic is packed into cells each containing a header portion containing virtual channel information for routing the packet to the desired destination. These cells are then routed across the ATM network and are subsequently unpacked to recover the data. Because the cells are assembled in an essentially asynchronous manner, the process is particularly advantageous for the transport of data.
Attempts to introduce ATM technology to distributed data processing systems has not been entirely successful for a number of reasons. Firstly, there is the problem of initial attachment to the network. In a conventional ATM network, every end system requires a unique address for receiving cells and must also access the network management system so that the launch of completed cells into the network from that end system can be controlled. This discovery and booting of an end system currently requires manual intervention which is slow and costly for a network operator and is inconvenient for the customer. Secondly, there is a requirement for an interface between the end system and the ATM network. Building a full ATM interface on each end system is expensive as a large volume of software is required on the end system.
In an attempt to address these problems it has been proposed that a proxy signalling provision in the ATM UNI version 4.0 Standard would allow a third party to perform Q.2931 signalling on behalf of an end system. However, this proposal still requires manual intervention to set up this feature as a special service and it requires manually provisioning a virtual channel (VC) from the proxy to the end system to instruct the end system on which virtual channel indicator (VCI) it should respond to. A further proposal requires the use of established addresses and ILMI protocols to discover a newly connected end system. However, this requires that the end system is self booting and has a Q.2391 protocol stack thus resulting in a relatively complex and costly arrangement.